(A Concise Guide to the Collection, Preparation, and Preservation of Herbarium Specimens, revised Oct 1997)

COLLECTION, PREPARATION, AND PRESERVATION OF HERBARIUM SPECIMENS

  1. Although various methods have been devised for preserving specimens of vascular plants, none surpasses the easy, inexpensive, efficient method of pressing and drying.

  2. In the field, specimens are carefully selected as representative of the population. Normally they are in flower and/or fruit. Underground parts of herbaceous plants are often diagnostic and should be dug up (using a strong trowel, brick hammer, screwdriver, etc.) where feasible.

  3. In the field, a record is made in a bound notebook of the collection number, date, location (country, state, county, legal description or longitude/latitude, verbal description, elevation, etc.), and habitat for each collection with notes where possible on associated species and on plant features (e.g., petal color, glaucescence, etc.) often lost in drying or otherwise not evident after pressing (e.g., habit, height, dbh., etc.)

  4. The plant is pressed as soon as possible for best results. If a field press is not used, the material is placed in a tagged plastic bag. Pressing can be delayed, often overnight, if the bags are kept cold (ice chest with ice; refrigerator).

  5. Preparation of a specimen for pressing includes removal of soil from roots and a judicious pruning of superfluous leaves, etc., without destroying parts necessary for identification. Plants that are longer than a folded half sheet of newspaper (e.g., Denver Post, or full sheet of Rocky Mountain News) are bent accordion-style (V-, N-, or W-shaped, etc.). Some leaves are turned over so both surfaces are displayed on the dried specimen. Extra flowers and/or fruits are included where possible. The collection number corresponding to the number in the collecting notebook is written on the sheet.

  6. After the plant(s) is positioned in the folded newspaper, it is placed between cardboard (12 x 18 in.) which serve as ventilators. The resulting pile of newspapers and cardboard is placed between press frames (a 12 x 18 in. lattice of ash or hickory slats, riveted or screwed together or sheets of exterior grade, 1/4 or 3/8 in. plywood) and tightly bound with two, 6-12 ft. long straps (webbing with buckles or sash cord with a loop in one end). To facilitate drying, the press is placed on an artificial heat source (e.g., plant dryer) or in the sun with corrugations parallel with the wind).

  7. If heat is not used, the pressing papers with enclosed plants may first be placed between two felt blotters or driers and then between cardboard. The blotters must be exchanged for warm, dry ones every day until the specimen is dry. The moist blotters are placed in the sun or against heating radiators to dry. This method is inefficient but sometimes unavoidable. A portable field dryer frame with heat source (electrical cord with 4 or 5 sockets and 150 watt light bulbs, hot plate, or kerosene or gas lanterns) works well on field trips.

  8. The dried specimens are stored in the numbered newspapers until identified and mounted.

  9. When the specimens are identified, neatly typed labels are prepared with the data (item 3) in the following order: scientific name with authority (e.g., Buchloë dactyloides (Nutt.) Engelm. or Quercus rubra L.), location, habitat, associated species, notes on plant features, date of collection, and the collector's name with collection number. The label, usually 25-100% rag paper, may be 4 x 2.5 in. or larger. Duplicate labels may be prepared on a high-quality photocopier.

  10. If the specimen is to be mounted, it should be attached to a sheet of 100% rag herbarium paper (11.5 x 16.5 in.). Mounting paper may be obtained from a biological supply house (as with the corrugates, blotters, and other supplies; see addresses below). The label is neatly glued to the lower right-hand corner of the sheet. The specimen may be attached with linen straps, thread, or glue (such as Elmers or Nicobond B), or a combination of these methods. If glue is used, it is spread in a thin layer over a sheet of glass or plexiglass (14 x 20 in or larger) with a paint brush. The specimen, face up, is placed firmly, but without smearing, on the glue, lifted with forceps, and carefully dropped in the desired position on the mounting paper. A piece of wax paper (12 x 18 in.) is then placed over it. The sheets with wax paper are stacked in a pile and a moderate weight is placed on top. When the glue is dry, the twigs and other bulky parts of the specimen are taped or sewn to the sheet for additional reinforcement or additional drops of glue are added.

  11. The mounted plant may now be placed with other specimens in standard genus covers in insect- and dust-proof herbarium cabinets housed in a dry place The sheets should be protected from insect attack by including a small container of paradichlorobenzene (PCB) in the case or by occasional fumigation (with chemicals by specially trained individuals or by placing the plants in a deep-freeze for several days). The climate throughout much of the Rockies is sufficiently dry that fumigation is not necessary.

__________________

Words in bold indicate the alternative used at the Rocky Mountain Herbarium

FOR ADDITIONAL INFORMATION ON FIELD AND HERBARIUM TECHNIQUES SEE:

Benson, L. 1979. Plant Classification. Heath and Co., pp. 423-444.

Forman, L. and D. Bridson. 1991. The Herbarium Handbook. Royal Botanical Gardens, Kew.

Jones, S. B., Jr., and A. E. Luchsinger. 1979. Plant Systematics. McGraw-Hill Book Co., pp. 138-156.

Lawrence, G. 1951. Taxonomy of Vascular Plants. Macmillan Co., pp. 234-262.

Savile, D. B. O. 1962. Collection and Care of Botanical Specimens. Publ. 1113, Research Branch, Canada Department of Agriculture.

Smith, C. E., Jr. 1971. Preparing Herbarium Specimens of Vascular Plants. Agric. Information Bull. 348, USDA (Superintendent of Documents, U.S. Govt. Printing Office, Washington D.C. 20402 (stock no. 001-000-01159-6).

SOURCES OF COLLECTING AND HERBARIUM SUPPLIES

Carolina Biological Supply Company, Powell Lab. Division, Gladstone, OR 97027 (503/656-1641; 800/547-1733)

Herbarium Supply Company, 3483 Edison Way, Menlo Park, CA 94025 (415/366-8868; 800/348-2338)

Pacific Papers, P.O. Box 606, Cotati, CA 94931 (800/676-1151)

St. Louis Paper and Box Company, P.O. Box 8260, St. Louis, MO 63156 (314/531-7900; 800/444-0891) 

FOR ASSISTANCE WITH PLANT IDENTIFICATION

(IN EXCHANGE FOR DUPLICATES):

  • Ronald L. Hartman, Curator E-mail: rhartman@uwyo.edu OR

  • B. E. (Ernie) Nelson, Herbarium Manager E-mail: bnelsonn@uwyo.edu

    Curator

    Rocky Mountain Herbarium

    Department of Botany (Dept. 3165)

    University of Wyoming

    1000 E. University Ave.

    Laramie, WY 82071-3165.

Phone: 307/766-2236
FAX: 307/766-2851

FLORAS USEFUL FOR PLANT IDENTIFICATION IN WYOMING

Albee, B. J., L. M. Shultz, and S. Goodrich. 1988. Atlas of the Vascular Plants of Utah. Utah Museum of Natural History, Occasional Publ. 7, xx + 670 pp.

Arnow, L., B. Albee, and A. Wyckoff. 1980. Flora of the Central Wasatch Front, Utah. Univ. of Utah Printing Service, Salt Lake City, xiv + 663 pp.

Barkley, T. M., ed. 1977. Atlas of the Flora of the Great Plains. Iowa State Univ. Press, Ames, xii + 600 pp.

Cronquist, A., A. H. Holmgren, N. H. Holmgren, and J. L. Reveal. 1972. Intermountain Flora. Vol. 1, Hafner Publ. Co.

Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1977. Intermountain Flora. Vol. 6, Columbia University Press, New York.

Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1984-1994. Intermountain Flora. Vols. 3B, 4, 5, The New York Botanical Garden, Bronx.

Cronquist, A., N. H. Holmgren, and P. K. Holmgren. 1997. Intermountain Flora. Vol. 3A, The New York Botanial Garden, Bronx

Dorn, R. D. 1977. Manual of the Vascular Plants of Wyoming. Garland Publ. Co., New York, 1498 pp.

Dorn, R. D. 1977. Flora of the Black Hills. Mountain West Publ., Box 1471, Cheyenne, WY 82003, x + 377 pp.

Dorn, R. D. 1984. Vascular Plants of Montana. Mountain West Publ., Box 1471, Cheyenne, WY 82003, iv + 276 pp.

Dorn, R. D. 1992. Vascular Plants of Wyoming. Ed. 2, Mountain West Publ., Box 1471, Cheyenne, WY 82003, iv + 340 pp.

Flora of North America Editorial Committee. 1993+. Flora of North America. Vols. 1-3, Oxford University Press, NY. (30 volumes upon completion).

Goodrich, S. and E. Neese. 1986. Uinta Basin Flora. USDA, Forest Service, Intermountain Region, Ogden, UT, xvii + 320 pp.

Great Plains Flora Association. 1986. Flora of the Great Plains. Univ. Press of Kansas, Lawrence, vii + 1392 pp.

Harrington, H. D. 1954. Manual of the Plants of Colorado. Sage Books. x + 666 pp.

Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. Univ. of Washington Press, Seattle, xix + 730 pp.

Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1955-1969. Vascular Plants of the Pacific Northwest. 5 vols., Univ. of Washington Press, Seattle as Vol. 17 of the Univ. of Washington Publ. in Biology

Lackschewitz, K. 1991. Vascular Plants of West-Central Montana--Identification Guidebook. USDA, Forest Service, Intermountain Res. Sta. General Tech. Rept. INT-277, 648 pp.

Nelson, B. E. 1984. Vascular Plants of the Medicine Bow Range. Rev. ed, Jelm Mountain Press.

Van Bruggen, T. 1985. The Vascular Plants of South Dakota. Ed. 2, Iowa State Univ. Press, Ames, xxv + 476 pp.

Weber, W. A. and R. C. Whittmann. 1996. Colorado Flora: Western Slope. Revised Ed. Univ. Press of Colorado, Niwot, 80544, xxxvii + 496 pp.

Weber, W. A. and R. C. Whittmann. 1996. Colorado Flora: Eastern Slope. Revised Ed. Univ. Press of Colorado, Niwot, 80544, xl + 524 pp.

Weber, W. A. and R. C. Wittmann. 1992. Catalog of the Colorado Flora: A Biodiversity Baseline. Univ. Press of Colorado, Niwot, 80544, xi + 215 pp.

Welsh, S. L., N. D. Atwood, L. C. Higgins, and S. Goodrich, eds. 1993. A Utah Flora. Ed. 2, Brigham Young Univ., Provo, vii + 986 pp.

FIELD LABEL

    *Collector _________________________________________ *No. __________

    *Date collected ___________________________________

    Family (or acronym) _________________________________________________

    Scientific name_____________________________________________________

    Locality, *State: _____________ *County: _______________________________

    *Verbal: ________________________________________________________

    ____________________________________________________________

    Township ________________ Range ________________ Section __________

    Elevation: _________________________________________________________

    *Habitat _________________________________________________________

    _____________________________________________________________

    *Occurrence: Common __________, Occasional ____________, Rare _________

    Plant Height__________________________ Flower color ___________________

    Remarks:________________________________________________________________

    ______________________________________________________________________________

    * Essential data, the remainder, can be obtained from maps, iding plant, etc.

SAMPLE LABEL